Aircraft engines are typically housed in a nacelle. A pylon extends from the nacelle to couple the engine to the aircraft. As one example, the pylon may couple the engine to a wing of the aircraft (e.g., the engine may be suspended below the wing). As another example, the pylon may couple the engine directly to the fuselage of the aircraft (e.g., the engine may be mounted to the side of the fuselage proximate the rear of the fuselage).
In modern aircraft, various steps are taken to inhibit the spread of flames to the wings and fuselage of the aircraft in the event of an engine fire. For example, all structural interfaces within the engine/pylon assembly are sealed with fireproof (or fire-resistant) material to eliminate gaps through which flames may propagate.
Structural interfaces vary with manufacturing tolerances and many are dynamic and, thus, are difficult to seal. For example, the interface between the forward side of the pylon and the aft side of the engine firewall can be quite dynamic—the engine firewall moves fore/aft, side-to-side and up/down relative to the pylon. A crossover seal is often positioned between the engine firewall and the pylon to provide the necessary seal, while accommodating the movement of the engine firewall. It is convenient when arranging the seal routings for the thrust reverser fire seal to lie over the crossover seal, but such a configuration may create gaps.
Accordingly, those skilled in the art continue with research and development efforts in the field of aircraft fire barriers.